<h2>
Answer with explanation:</h2>
As per given , we have
Sample size : n= 5
Degree pf freedom = : df= 5-1=4


Significance level for 90% confidence = 
Using t-value table , t-critical value for 90% confidence:

Margin of error of
: 
Interpretation : The repair cost will be within $12.39 of the real population mean value
90% of the time.
Angle 3 is 99 degrees.
Angle 2 is 61 degrees.
angle 1 is also 61 degrees.